阅读下面短文，从短文后各题所给三个选项（A、B、C）中，选出可以填入空白处的最佳选项。

    Today, I am going to talk about life in the future. 1 will life be like in the future? No one can answer this question. Today, 2 in space can take photos of places billions of light years (光年) 3 the Earth. Science is developing very fast and people know more about space. 4 the help of science, we may also visit those places. We may have to 5 the Earth to live in space because the Earth will not hold so many people 6.

    In the future, we will travel very fast by 7. Our spaceship will be 8 a city, and every ship will carry 9 10, 000 people. There are also many buildings in our ships 10 hospitals, schools, shops and cinemas.